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#### harrysin

Retired since June 2000
Joined
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15,066 Posts
Hello T. I read you post on using Excel to list guide bushings and bits. I wondered if you have done this and if you could email me that Excel file. It would help me set it up and use it.

Tom VB
Tom, whilst charts are useful, like with calculators or electronic cash registers, things can happen to them and so one must be able to use paper and pencil, or better still, calculate in one's head. in a similar fashion, a competent routologist should be capable of calculating off-sets, it really is so simple, template guide diameter minus bit diameter divided by two equals the OFF-SET, or to calculate the size of opening in the template for a given size opening in the finished project: guide dia. minus bit dia. plus finished size of opening equals the size of opening in the template. An example, we wish to rout an opening 9" x 4.5" and we use a 1.5" guide with a 0.25" bit, 1.5" - 0.25" + 9" = 10.25"
1.5" - 0.25" +4.5"= 5.75"
so, the opening in the template has to be 10.25" x 5.75" to end up with an opening in the finished project of 9" x 4.5"
Understanding this means that no project will be held up if the dog chews the chart!

#### harrysin

Retired since June 2000
Joined
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15,066 Posts
While I agree with Harry that having the simple offset formula stored in the cranium is good, I made up a chart for my commonly-used bushings and bits and taped it to the inside of the plastic bushing container. That way, the dog must eat the plastic to get to the chart. And, two coats of cat urine on the container will dissuade all but the most determined dogs.

Oh, and don't forget the utility of bushing collars to add to the offset.
I think this is what you mean Ralph.

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